Centrally Controlled Coke Oven Aeration System for Primary and Secondary Air

ABSTRACT

This invention relates to a ventilation device for non-recovery coke ovens, said ventilation device consisting of at least one vent port extending through the wall or built-in internals, e.g. a coke oven door, and connecting the oven interior with the outer atmosphere surrounding said oven and wherein said vent port can be closed entirely or partly by means of a locking element. Two locking elements or more are coupled to each other by at least one mechanical coupling element by fastening said coupling element to said locking elements directly or via a lever, and wherein each coupling element is connected to at least one central adjusting element such that said locking elements can be moved, with it being possible for the relevant vent ports to be closed, completely opened or moved into any intermediate position. Ideally this coupling element should be a chain or a screw spindle.

This invention relates to a device and a method for supplying combustionair for the combustion of coking gas in cokemaking chambers of cokeovens built in flat-type construction and arranged as a battery of cokeovens for the so-called non-recovery or heat-recovery process. Thisdevice at least comprises a vent port for each cokemaking chamber, saidvent port extending through the relevant coke oven door or its wallsurrounding it, as well as vent ports for supplying secondary air intothe heating flues. A freely-supported locking element is provided foreach vent port.

All locking elements are mechanically connected to at least oneadjusting element controlled and driven from a central point. Theadjusting element continuously actuates the locking elements dependingon the demand for combustion air in the cokemaking chamber. Themechanical connection of each individual locking element with thecentral adjusting element can be effected separately, wherein especiallythe starting position of each individual locking element at thebeginning of the cokemaking process of the pertaining cokemaking chambercan be adjusted independently of the other locking elements of theadjacent cokemaking chambers.

Heating of heat-recovery ovens is usually performed by combustion of gasevolving on cokemaking. Combustion is controlled in such a manner thatpart of the gas above the coal charge burns off with primary air in theoven chamber. This partly burnt gas is fed through channels that arealso designated as “downcomers” to the heating flues in the oven chambersole and completely burnt there by the addition of further combustionair, which is called secondary air.

In this way, heat is directly supplied from the top and indirectly fromthe bottom to the coal charge, thus taking a positive impact on thecoking rate and, thereby, on the performance rate of coke ovens. Toexecute the method it is required to exactly rate and variably controlthe supplied primary and secondary air throughout the carbonisation timethat may take up to 20 to 96 hours. Heat-recovery and non-recovery cokeovens in flat-type construction are widely described in prior artdisclosures. For example, reference is taken to U.S. Pat. No. 4,344,820,U.S. Pat. No. 4,287,024, U.S. Pat. No. 5,114,542, GB 1 555 400 or CA 2052 177 C.

According to the conventional state of the art in technology, primaryair is sucked in from the atmosphere through ports in the doors.Secondary air is sucked in through ports near to ground and conductedthrough channels into the heating flues which mainly extend horizontallyunder the coke oven chamber. The ports for primary and secondary air areeither opened permanently or provided with flaps designed to adjust theamount of air to be aspirated.

As the coke oven batteries are very extensive, and since usually a veryhigh temperature prevails therein and because a serious development ofdust is encountered, only manually adjustable ventilation flaps aredisclosed in prior art technology. U.S. Pat. No. 5,928,476 describessuch a coke oven battery, wherein three manually operable ports areprovided in each coke oven door, in which or in front of which one plateor disk each adapted to the port cross-section and supported at acentral axle is arranged. These port flaps can be varied in theirposition manually through levers.

In practice, however, it becomes evident that the required variation inthe amount of primary and secondary air throughout the carbonisationtime is effected with a manual adjustment only in very isolated casesand that the ideal time-dependent adjustment is thus by far notachieved. Furthermore, manual operation implies a serious burden tooperators' health.

Now, therefore, it is the objective of this invention to remedy thedescribed deficiencies in an economic manner and to assure an optimisedsupply of primary air and/or secondary air. Operational safety must beassured even with usually high temperatures and heavy impurities.

This invention solves this task by providing a device for supplyingcombustion air for the combustion of coking gas in cokemaking chambersof coke ovens built in flat-type construction and arranged as a batteryof coke ovens, wherein the venting device consists of at least one ventport for each cokemaking chamber, said vent port extending through therelevant coke oven door or through its wall surrounding it, and whereina freely-supported locking element is provided for each vent port,wherein

-   all locking elements of these vent ports are mechanically connected    to at least one adjusting element controlled and driven from a    central point,-   the locking elements are to be actuated by means of said adjusting    element depending on the demand for combustion air in the cokemaking    chamber,-   the mechanical connection of each individual locking element with    the central adjusting element can be effected separately, wherein    especially the starting position of each individual locking element    at the beginning of the cokemaking process of the pertaining    cokemaking chamber can be adjusted separately and independently of    the other locking elements of the adjacent cokemaking chambers.

The connection between the locking element and the adjusting element asused hereunder shall be understood to mean that both elements may beconnected to each other in a detachable way through a coupling element,for example a lever, rope tackle, chain, lever arm, etc. as well ascombinations of these elements.

Advantageous embodiments provide for configuring the adjusting elementas a rotating chain or as a steel cable. Using a screw spindle asadjusting element is another suitable embodiment. All these adjustingelements permit a permanent actuation into one moving direction which isvery advantageous for the continuous overall process.

Furthermore, the device embodying this invention can be configured insuch a manner that locking plates are installed as locking elements,said locking plates being supported in such a way that when actuated bythe coupling element they are moved mainly in parallel to the oven door.

For a directed flow of primary gas it is of advantage for the vent portto be of a rotary-symmetrical shape. Therefore, the use of lockingelements configured as upright standing locking plates and supported invertically or horizontally rotatable arrangement around a central axleis advantageous.

With a further improved embodiment of said ventilation device, thelocking elements are formed by at least two overlapping and reciprocallyslideable facettes, with both facettes ideally exposing a polygonal andpoint-symmetrical or nearly circular cross-section when partly opened.Hence, there is no diversion of aspirated air in the vent port andbecause of the higher flow velocity the aspirated air is directed moredeeply into the oven space.

A still advanced improvement resides in configuring the locking elementsin conical shape, with the tip pointing towards the oven interior whenbuilt-in. This embodiment can still be further optimised in such a waythat the vent port has the same or a wider angle of aperture than thepertaining conical locking elements. In this embodiment of the lockingelement for the device embodying this invention, the aspirated air iswhirled-up minimally in the area of the locking element as well as inthe area of the vent port and shaped to a gas jet independently of thesize of the exposed cross-section.

With a different size of the conical angles of the vent port and lockingelement it can be assured that impurities accumulating in the vent portdo not prevent a complete closure of the vent port. The conical lockingelement is moved via a lever structure and/or a spindle in thelongitudinal direction of the vent port so that a circular ring gap isexposed when partly opened.

The ventilation device can be further improved by connecting the lockingelement with the adjusting element in such a way that it isautomatically released from the adjusting element when being in the endposition and when the vent port has been completely closed.

This invention furthermore comprises a device for supplying combustionair in coke ovens, in which the ventilation device embodying thisinvention as described before is implemented by one of its embodimentvariants, with the sequence of the method being as set forth below:

-   a) After discharging and recharging a cokemaking chamber said    locking elements are moved into the starting position that    represents the complete or nearly complete opening of said vent    port, and wherein said locking elements are connected to the central    adjusting element.-   b) During the carbonisation time, the locking elements are actuated    by the central adjusting element continuously and mainly at the same    medium speed or actuation frequency so that the vent ports are    continuously closed.-   c) Latest at the end of the carbonisation time of a cokemaking    chamber will the locking elements have completely closed the vent    ports of this cokemaking chamber and can be released from the    adjusting element.-   d) Upon discharging and recharging, the method is restarted again by    taking step (a).

An improved variant of this method is that the locking element being inthe end position is automatically released from the adjusting element.

In another improved embodiment of the process embodying this invention,at least two central adjusting elements are provided for, wherein oneadjusting element thereof actuates the locking elements for primary airand wherein the other central adjusting element actuates the lockingelements for secondary air. Throughout the entire carbonisation time,the two adjusting elements are controllable completely independently ofeach other.

It is advantageous to actuate one central adjusting element continuouslyand mainly at the same speed or actuation frequency.

This invention also encompasses the use of the ventilation deviceembodying this invention in one of the embodiment variants outlinedhereinabove with a method for supplying combustion air in cokemakingchambers of coke ovens built in flat-type construction and arranged as abattery of coke ovens.

This invention is described by way of three exemplary embodimentvariants illustrated in FIG. 1 to FIG. 3, with the invention not beingrestricted to these examples of embodiments. FIG. 1 shows a coke oven 1in a front view. In its front area, coke oven 1 has a coke oven door 2in which two vent ports 3 for primary air are arranged. Located beneathsaid coke oven door 2 and illustrated by dotted lines are heating flues4 extending under the oven space. The vent ports 5 for supplyingsecondary air into these heating flues 4 are arranged near the bottombeneath said heating flues 4.

Moreover, FIG. 1 shows the locking elements 6 for said vent ports 3 ofthe primary air supply and the locking elements 7 for the vent ports 5of the secondary air supply. Each locking element mainly consists of alocking plate 9 and a lever arm 10 and it is supported at an axle 8around which said locking element can be moved in rotating motion. Thelever arms 10 of said locking elements 6 are connected in a detachableway with a rotating chain 11 and the locking elements 7 are connected ina detachable way with a rotating chain 12.

By a continuous movement of chain 11, the locking elements 6 are movedin counter-clockwise direction around the angle a while the lockingelements 7 are moved in clockwise direction around angle β. The chainsare driven via the central adjusting elements 13 and 14, respectively.

FIG. 2 shows the front view of two coke ovens 1 representing a majorcoke oven battery as indicated by the two arrows I and II. These twocoke ovens 1 are at different stages of coal carbonisation. The cokeoven 1 shown on the right side is in the initial stage of coalcarbonisation, and therefore the locking elements 6 hardly overlap thevent ports 3. In this example of the embodiment, the lever arm 10 isconnected via a minor chain 15 to the rotating chain 11. The arrangementin the area of the vent ports 5 for secondary air is analogous. Here,the locking elements 7 and, respectively, their lever arms 10 areconnected via minor chains 16 to the rotating chain 12.

The supply of air to the coke oven 1 shown on the left side has alreadybeen closed completely and the lever arm 10 and the chain 15,respectively, have been released from the rotating chain 11. The lockingelements 7 for the control of secondary air of the coke oven 1 shown onthe left side are at a stage shortly before closure, but they are notyet closed completely. Hence, it is well conceivable that each coke oven1 can be controlled absolutely individually despite a common centralcontrol.

A special embodiment variant of the locking elements 6 and 7 isillustrated in FIG. 3. Shown in this sectional drawing is arotary-symmetrical locking element 6 having a locking head 17 in form ofa truncated cone to which a cylindrical guiding rod 18 is fastened. Theguiding rod is firmly connected to a spring bridge 19 fastened to saidcoke oven door 2. The guiding rod 18 is guided in a guiding tube 20 andconnected with its rear end via a small chain 15 to the rotating chain11. At the beginning of the carbonisation time, the springs of thespring bridge 19 are pre-stressed by expansion so that the vent port 3is largely open. By the movement of the rotating chain 11 the springbridge 19 is relieved, the locking element 6 is moved in the directionof the coke oven door 2, and the locking head 17 is introduced into theconical vent port 3. The pre-stressing shall be chosen such that afterrelief of the chain 15 and spring bridge 19 a complete closure of ventport 3 is achieved.

List of Reference Numbers

-   1 Coke oven-   2 Coke oven door-   3 Vent port (primary air)-   4 Heating flues-   5 Vent ports (secondary air)-   6 Locking elements (primary air)-   7 Locking elements (secondary air)-   8 Hinge-   9 Locking plate-   10 Lever arm-   11 Chain (primary air)-   12 Chain (secondary air)-   13 Adjusting element-   14 Adjusting element-   15 Chain-   16 Chain-   17 Locking head-   18 Guiding rod-   19 Spring bridge-   20 Guiding tube

1-17. (canceled)
 18. A ventilation device for supplying primary andsecondary air for the combustion of coking gas in cokemaking chambers ofcoke ovens built in flat-type construction and arranged as a battery ofcoke ovens, wherein said ventilation device consists of at least onevent port per cokemaking chamber for primary air, said vent portextending through the relevant coke oven door or through its wallsurrounding it, said ventilation device furthermore comprising at leastone vent port per cokemaking chamber for secondary air and whereinfreely-supported locking elements are provided for at least part of saidvent ports, comprising at least part of the locking elements of saidvent ports is mechanically connected to an adjusting element controlledand driven from a central point, said locking elements can be actuatedby said adjusting element depending on the demand for combustion air inthe cokemaking chambers, the mechanical connection of each individuallocking element with the central adjusting element can be effectedindividually, wherein especially the starting position of eachindividual locking element at the beginning of the cokemaking process ofthe pertaining cokemaking chamber can be adjusted separately andindependently of the other locking elements of the adjacent cokemakingchambers.
 19. A ventilation device according to claim 18, wherein atleast part of the locking elements for primary air is mechanicallyconnected to an adjusting element and wherein at least part of thelocking elements for secondary air is mechanically connected to anotheradjusting element.
 20. A ventilation device according to claim 18,wherein the adjusting element is a rotating chain.
 21. A ventilationdevice according to claim 18, wherein the adjusting element is a screwspindle.
 22. A ventilation device according to claim 18, wherein thelocking elements are locking plates which are supported such that theyare moved mainly in parallel to the oven door when they are actuated bythe connecting element.
 23. A ventilation device according to claim 18,wherein the locking elements are upright standing locking platessupported in vertically or horizontally rotatable arrangement around acentral axle.
 24. A ventilation device according to claim 18, whereinthe locking elements are formed by at least two overlapping andreciprocally slideable facettes, wherein both facettes ideally expose apolygonal and point-symmetrical or nearly circular cross-section whenpartly opened.
 25. A ventilation device according to claim 18, whereinthe locking elements are conical, with the tip pointing to the oveninterior when built-in.
 26. A ventilation device according to claim 25,wherein the vent port has the same or a wider angle of aperture than thepertaining conical locking elements.
 27. A ventilation device accordingto claim 25, wherein the conical locking element can be moved in thelongitudinal direction of the vent port, thereby exposing a circularring gap when partly opened.
 28. A ventilation device according to claim18, wherein the locking element is connected to the adjusting elementsuch that when being in the end position and when the vent port has beencompletely closed, it is automatically released from the adjustingelement.
 29. A method for supplying combustion air for the combustion ofcoking gas in cokemaking chambers of coke ovens built in flat-typeconstruction and arranged as a battery of coke ovens, wherein at leastone device according to claim 18, is implemented, wherein a) afterdischarging and recharging a cokemaking chamber said locking elementsare moved into the starting position that represents the complete ornearly complete opening of said vent port, and wherein said lockingelements are connected to the central adjusting element, and whereinsubsequently b) during the carbonisation time said locking elements areactuated by the central adjusting element(s) such that the vent portsare more and more closed, and wherein subsequently c) the lockingelements of a cokemaking chamber have attained their end position latestat the end of the carbonisation time of the relevant cokemaking chamberand are released from said adjusting element, and wherein d) said methodaccording to (a) is restarted again.
 30. A method according to claim 29,wherein after the complete closure of the vent port the release of saidlocking elements from the adjusting element is effected automatically.31. A method according to claim 29, wherein throughout the entirecarbonisation time the central adjusting element is actuatedcontinuously and mainly at the same medium speed or actuation frequency.32. A method according to claim 29, wherein at least one centraladjusting element for the locking elements of primary air and at leastone central adjusting element for the locking elements of secondary airare provided for.
 33. A method according to claim 32, wherein thecentral adjusting element for primary air and the central adjustingelement for secondary air are actuated continuously throughout theentire carbonisation time and mainly at the same medium speed oractuation frequency.